Wavelength Tuning of Multimode Interference Fiber Lasers: A Review

Herein, the main aspects of fiber lasers are summarized where multimode interference (MMI) is underlying phenomenon for wavelength tuning mechanism. Also, 15 years work in field covered, from its first report, 2005, to most recent publications, 2020. In addition historical perspective, insights into different mechanisms also provided that exploited tune spectral response MMI filters used lasers, among which free space, optofluidic, stress optic, thermo and nonlinear mechanisms.